Former CIA director David Petraeus admitted he made a huge mistake by having an extramarital affair with his biographer Paula Broadwell, according to a close friend. 

Petraeus,60, had been relatively silent in regarding to addressing the public and making an official statement to reporters about his affair, which ultimately resulted in his stepping out from his government position. However, he did talk to friends about the matter. He wrote a letter to a former mentor of his, retired Brigadier Gen. James Shelton, after he reached out to Petraeus when the scandal surfaced earlier this month. 

Shelton showed the letter to ABC News, in which Petraeus thanked Shelton for his concern and support, and admitted "I screwed up royally, I paid the price appropriately" regarding his affair with Broadwell, 40. He also said "Team Petraeus will survive though."

Shelton said he and Petraeus have been friends for more than three decades. In the letter, Petraeus also said his wife is "...once again demonstrating how incredibly fortunate I was to marry her." Previous reported stated that Petraeus' wife threatened her husband with a divorce after 38 years of marriage because of the humiliation he caused her. The couple have two adult children together, one of which served in Afghanistan. 

Shelton said he never met Broadwell but he helped her with her biography of Petraeus, "All In: The Education of General David Petraeus," according to the news report. He spoke on the phone will her and Broadwell thanked the retired general in her book's acknowledgements for "being wonderfully helpful."

He added that he was disappointed in Petraeus' actions, but noted that the blame should not be fully on him and that "it was mutual" between him and Broadwell. 

Petraeus told friends the affair with Broadwell began in August of 2011 after he left the army. Ironically enough, Broadwell wrote in her book Petraeus' relationship with his wife, Holly, was "virtually unbreakable."

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